Monroe County, IN, 2010 Orthophotography

The purpose of this project was to update the county's raster database with color orthorectified imagery.

Description

Digital orthophotographs are orthorectified aerial photographs.
These orthophotos were flown April 2, 2010, with a resolution of 0.5 feet.
Coverage areas for this flight date are for all of Monroe County, Indiana

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Access and use limitationsThere are no access and use limitations for this item.

Digital Orthophotographs are orthorectified aerial photographs. These orthophotos were flown April 2, 2010 with a resolution of 0.5 feet. Coverage areas for this flight date are for all of Monroe County, Indiana.

Purpose

The purpose of this project was to update the county's raster database with color orthorectified imagery.

During the digital image post-processing, automatic dodging is performed to improve image quality. Dodging the images consists of balancing the radiometry of individual photographic exposures to eliminate flares and dark areas. The images are inspected to ensure clarity and radiometric uniformity. Image brightness values may deviate from brightness values of the original imagery due to image value interpolation during the post-processing and rectification processes. Radiometry is verified by visual inspection and histogram calculations of the digital orthophoto quadrangle with the original unrectified image to determine if the digital orthophoto has the same or better image quality as the original unrectified input image. Each image is rated on a pass-fail basis using metrics agreed upon by the county.

Quantitative Attribute Accuracy Assessment

Attribute Accuracy Value Scan Resolution

Attribute Accuracy Explanation

12 microns

Quantitative Attribute Accuracy Assessment

Attribute Accuracy Value Image Resolution

Attribute Accuracy Explanation

0.5 foot

Quantitative Attribute Accuracy Assessment

Attribute Accuracy Value Original Photo Ratio Scale

Attribute Accuracy Explanation

1" = 100'

Logical Consistency Report

All image header data and image file sizes are QC'ed using both manual and automated processes.

Completeness Report

All imagery is visually inspected for completeness to ensure that no gaps, or image misplacement exist in the overlapped-square image sheets. The ortho images may be derived by mosaicking multiple images, in order to ensure complete coverage. Source photography is leaf-off in deciduous vegetation regions. Photo coverage for Monroe County consists of 24 flight flines with a total of 1973 exposures flown at an altitude of 4800 feet. Overlap between each exposure is 60% with a 30% sidelap between flight lines. Direction of flight is North-South.

Positional Accuracy

Horizontal Positional Accuracy

Horizontal Positional Accuracy Report

Meets National Standard for Spatial Data Accuracy of 2.5 feet horizontal accuracy at 95% confidence (National Map Accuracy Standard), Accuracy of this data set is average of 1.314 survey feet.

Quantitative Horizontal Positional Accuracy Assessment

Vertical Positional Accuracy

Quantitative Vertical Positional Accuracy Assessment

Lineage

Source Information

Source Citation

Citation Information

Originator GE Energy/ MJ Harden Associates, Inc.

Publication Date Unknown

Publication Time Unknown

Geospatial Data Presentation Form vector digital data

Source Scale Denominator 1:1200

Type of Source Media Hard Drive

Source Time Period of Content

Time Period Information

Single Date/Time

Calendar Date 2010-04-02

Source Currentness Reference

publication date

Source Contribution

MJ Harden Associates, Inc.

Process Step

Process Description

Aerial acquisition was performed using a digital mapping camera. Raw imagery post-processed as panchromatic and pan-sharpened using color RGB channels of imagery to output raw data for use in photogrammetric workflow.
Control Survey- performed by Schneider:
1. Airborne GPS/IMU with DMC
2. 20 control points
The elevation model (DEM) used to rectify the images was completed by MJH . The DEM will include modification of the elevation data at bridges, overpasses and areas with major terrain irregularities to eliminate the possibility of "image smears".
The orthorectification "process" will be accomplished using exponential interpolation parameters. Exponential interpolation algorithms provide an extremely robust rectification process.
Tiling Schema:
Tiling Schema was based on a 5000x5000' grid.
All associated metadata will be provided.